1 62 FUMIGATION METHODS 



difference in the resisting powers of various species of 

 insects is so slight we generally recommend for indoor 

 fumigation the use of the 0.25 gramme formula. Un- 

 der no circumstances should a less amount be used, 

 unless specifically designated by an expert. 



Some beetles require the full strength to destroy 

 them in most enclosures. This is particularly true of 

 the bolting-cloth beetle, Tenebroides mauritanicus , and 

 its young, a small, flat, whitish, greasy-looking crea- 

 ture, about one-third to one-half inch long, familiar to 

 millers ; the flour beetle, Tribolium confusum, and its 

 young ; the grain weevils, Calandra granaria and C. 

 oryza ; and the American meal worm, Tenebrio molitor. 

 In fact, nearly all the beetles commonly found in mills 

 and other enclosures where farinaceous foods are stored 

 or manufactured are not as easily killed with the gas 

 as moths and their young. Bearing these facts in 

 mind, it is, therefore, best to use the gas in accordance 

 with the 0.25 gramme formula. 



Estimating chemicals. The amount of cyanide 

 necessary for any enclosure is determined in terms of 

 grammes per cubic foot of space enclosed. To deter- 

 mine the exact amount of cyanide necessary to fumi- 

 gate a room, car, ship, or building of any kind, the 

 cubic contents must be accurately computed. As an 

 example, a room 20 x 30 x 10 feet contains 6,000 cubic 

 feet of air space. To estimate the amount of cyanide 

 required for this enclosure, multiply 6,000 by 0.25 ; 

 thus: 6,000x0.25= 1,500 grammes. To reduce this 

 to ounces, divide by 28.35, as there are 28.35 grammes 

 in an ounce; thus: 1,500-4- 28.35 = 53 ounces, the 

 exact amount of cyanide needed for the enclosure. It 



